US2925264A

US2925264A - Torsion spring suspension for wheeled vehicles

Info

Publication number: US2925264A
Application number: US640658A
Authority: US
Inventors: Leslie K Loehr
Original assignee: Individual
Current assignee: Individual
Priority date: 1957-02-18
Filing date: 1957-02-18
Publication date: 1960-02-16
Anticipated expiration: 1977-02-16

Description

Feb. 16, 1960 L. K. LOEHR TORSION SPRING SUSPENSION FOR WHEELED VEHICLES Filed Feb. 18. 1957 2 Sheets-Sheet 1 5 Imam-0R Feb. 16; 1960 L-/K. LOEHR' 2,925,264

ToRs IoN SPRING SUSPENSION FOR WHEELED VEHICLES Filed Feb. 18. 1957 2 Sheets-Sheet 2 'INVENTOR,

In the drawings:

Fig. 1 is an oblique view of a tubular spring element embodied in this invention;-

Pig. 2, is aside elevation of an automobile left-frontwheel fsuspensio'n constructed aocordin'g'to thisjinvention; Fig. 3 is a combination plan and sectional view of the left-'fro'nt whe'el suspension system in Fig. 2 taken on line 3-13; V I

.Fig. .74 is a side elevation ofan automobile left-rear- Wheel, suspension system constructed according to this invention;

,Fig. '5, is a combination plan and sectional view of the'leftE'rear-wh'eel suspension system in Fig. 4, taken on line 5-;5; H

:Fig. ,6 .is ane'nd view taken .on line 6=-6 of Figv 5 showing .the b'raclgets for-attaching the suspension systen' totheautomobile-frame; I .-Fig. 7 is a viewshowin'g asideelevationof a dual or tandem -axle suspension ,isystemgconstructed "according to this invention taken'on linev 7 "7 of-Fig.6; t

;Fig..8 ajsectional viewtaken on line 8;8of1.Fig.,.7; -Fig. .9 is anendyiew-taken on line 9 9 of Fig. 8; Fig. 10 is a sectional view taken-on line 10-10 of Fig.

Fig. 11 is a sectional view taken onlin'e 11--11 of'Fig.

Fig. 12 is aplan view of the bracket usedin. Fig. 7 for connecting the spring system "to the vehicle frame; and

Fig. 13 isa-view taken gonline 13-'-13 ofFig. 12, showing an endelevation of the bracket.

The torsion spring embodied in this invention and illustrated generally in Fig. 1 comprises a tubular element 2110f spring material in which the generallycylindrical wall ofthe element'is longitudinally severed throughout its length by a slot 21 whereby torsional flexibility of the element is effectively increased to a magnitude greatly exceeding the flexibility of a solid-walled tubeof similar dimensions. As illustrated, element 20 is in a torsionally stressed or twisted condition of 45 degrees resulting from twisting forces applied at right angles to the element axis by torque arms '22 and 23 having portions circumaxially embracing the ends of the elementjsuch as toiprovide radiali'ibs' or flanges '24 arid 25 welded to the element wall, which ribs orffla'nges are madediscontinuous' by 6peningsj26 and" 27 radially aligned with slot 21. This structure for applying twi'sting'forces to element j20'i1ot oh'lj'pr'eser'ves the torsio nal' flexibility of the "e leme'nt' in the regions of 'the"fla nges,fbut"it also"provides radial rigidity to prevent" radial spreading of the element wall in theregio'ns where the" twisting forces are applied.

In Figs. 2 and 3 there is illustrated'an "independent wheel'fsuspension assembly adapted for use'with'the front Wheels of an" automobile, which'incorporates a'spring suspension system identified by'reference letter A having a torsion spring similar in structure and function to spring element 20 of Fig. 1. In this assembly upper and

lower control arms

16 and 18 connect a left-front. wheel schematically represented by line 30, to a vehicleframe having'aleft-ffont side portion 31 and a longitudinal axis 32. Asshown, wheel'30 is mounted on a spindle 33 of a steering knuckle 34 sup ort d for the vehicle steering function byf ar'ms 16 and 18 according" to' prior art teaching's; while the control armstheni 1v "'a re hinged'to the vehicle frame about respective axes"35""a'nd"40 extending lengthwise of the vehicle frame such that up and down movement of steering knuckle '34' relative to theframe is confined to aigenerally vertical 'plaiie extending-transversely 'of saidfra'me. 3

TIE-hehiilgedrelationship ofaim 1610 the" vehicle frame abputaxis '35 is efiected in any well known ma'nner such as by r neans of.-a bracket '37: securelyi'attach'ed to the amsnatc ,.otircnt de po n 1 and n ep adjustably supported by the bracket. It is. to 'be noted that axis 35 is coincident with the axis, Of the hinge pin, and that the coincident axesare purposely sloped downwardly toward the rear of the frame ,as seen in Fig. 2 to promote a trailing condition to be described later.

For purposes of description, control arm 18 will hereinafter be referred to as suspension member 18; hence, according to this invention spring suspension system A is a generally triangular structure comprising a suspension member E8 having a pair of

divergent pivot arms

42 and 43 extending from a suitable connection 41 with steering knit aide 34 "to spaced-apart

pivotal connections

44 and 45 with

crossmembers

46 and 47 of the vehicle frame, and a split-walled tubular spring element 20 disposed between these ipivot'al connections. As shown, spring element 20' and

pivotal connections

44 and 45 are arranged such that the longitudinal axis of the spring element and the pivotal axes of the connections are coincident with -axis40. *It-isalso to -be -n'otedtthat the ends of the spring element are rcspectivelymonnected"to crossmeniber 46 and :pivotwarm'43 -by torque arms 22 and 23',- 'constr'ucted -simila'r 'to arms, 22 and '23 described in connection with Fig. 1, such that pivotal'bfswinging movements' of suspension member 18 aboutpivotal connections Marni 45 are effective for'causing'torsional deflection of tubular spring element 20 about axis 4% In other words, when loadsresulting-fremthe weiglit of the vehicle are supported -by a wheel 3i]? 'mounted on spindle 33, -such-loads are 'resolve'das-forces applied to suspension member '18 by "steering knuckle 34 "at connection '41 such :as to cause 'snspensioninember 13 to rotate upward-1y about axis 40'towardframeportion 31 in direct proportion 'to'thetorsional deflection produced in spring element 20 by torqueia'rms 22ian'd 23'.

As-jillustrated 'invFigs. 2"and 3, the: pivotafconnections 44 and '45 betweenarms 42 "and 43 and "frame crossupwardly with respect to "axis 32 from crossnnember 46,

to crossmember -47. f'St'ated-difierently, axis til-slopes downwardly fromthe front *of thefrarne to intersect a ground plane supporting wheel'30,inwardly-fromthe left-front side of the frame to 'intersect'-a vertical plane extending throughaxis 32.

The canted or sloped conditions' of axes-'35---and' 40 with respect to the longitudinal axis-32 'of the vehicle frame produce 'a trailing relationship of wheel 30 with respect to the frame whereby the forces of motion, as the vehicle moves forwardly, actto :pull the. wheel over the ground plane or surface'of a "roadway. This trailing relationship is eflective for reducing the magnitude of road shock transmitted to the'vehicle frame because it improves the ability of the wheel to pass over obstructions frequently encountered on roadway surfaces. The advantages resulting'from the trailing relationshipof'the wheel to the frame are clearly analogous to the advantages of pulling, as compared to pushing, a loaded wheelbarrow over rough ground or over-an obstruction in thepath. of the whee1- of -the'barrow. 1 Moreover, the generally longitudinal positions 'of axes; 35. and '40 producein spring suspension-A, the trai-ling relationship between wheel 30 and the vehicle frame such that brake reaction forces or driving 'r'eactionforc'es resulting from braking forces ordriving forces applied to" wheel 30 are absorbed by the frame without producing' forces tending to twist @spring element 20';--hence, *braking-or-drivmg w yer forces donot influence the relative position oj rne mbcr r 18 with respect to the vehicle frame. i

Whiletorque arms 2 2 and 23" are constructed 'and and 45. Other means of supporting spring element 20'; a

in its r p rp t q ll q e par m om tre e t h naf e de r bed r In Figs. 4 5, and 6 there is illustrated 'a sprr ggsus: pension system identified by reference :letter B "which mp o tm i n. rin s i ti ma ure an fim ti to ms tz lbt i -:1 a -whi h-l s t m ar able, in general, for usein' wheeled'vehielesja parmotive yehiele. irks applied to aleft-rear drivingwheel schematically representediby ajcircular line 54, system,

B is a spring suspension means :hingedly disposed about an axis longitudinally associated with a vehicle t r ame having a lengthwise axis 32' and'a left-rear v side portion 56: su ch as to resiliently connect end 58a offa wheels supporting rear axle housing 58 to the vehicle frame} and such that the wheel-supporting axlehousing is. movable up and down relative to the frame in a generally; cr tical plane extending transversely of I said frame.

System B is a generally triangul r structure comprising asuspension member. 60 havinga pair of divergent ivot V arrrisj 6l' and 62 extending tra a unction 63: to; spaceii apart axially aligned pivotal'ifconnections 64 audr65- with br'ackets66and 67, respectively, of which bracket;66v is riveted to frame side-portion 5 6Vand bracket 67'i s; fixedly mouhtedjo'na frame crossme'nibert68gand a generally cylindiical'fsplit walled tubular.spring elementfill dis posedbetwe'en the pivotal connections 64and 65 such thatith longitudinal axis-of-Qthelspring elementis aligned with the axes of the pivotal connections. 1 In Figs. 5 and 6; it is seen that vthefloc'zation of brackets 66. and 67 relative'to the rear side portion 56fof the vehicle frame, position pivotal a

connections

64 and 65 such 'that axis 55/is obliquely disposedwithrespect to a; vertical plane extending through axis 32'Lof'the vehicle'frame for: providing a trailing relationshipbbetween 'iwheelj 54 '(as s up ported by rear axle housing 58) and the vehicle frame.

According to Fig, 5, pivotal connection 64 is effected bymeans of a stub shaft 72 havinga cylindrical portion 73, of reduced diameter in rotative engagement with. a

bore in the-distal end ,o f p ivot arm 61 and a threaded 70 ,arellocated gsiibistantially diametrically opposite the rotating relationship is efiectedj by astationary torque arm 8 1 having a-bored endradially embracing end-70a of the element, and by a cap screw 85 extending through 1 radialopenings ingthe bored end of thetorque arm and element end 70a into a; threaded engagement with stub shaft 72; while the driving relationship is efiected by a cap screwf86 extending through a radial opening in a collar 87 radially embracing end70b of the spring element and a radial opening in sa id;end 705 into a threaded engagement with boss 02, all according to similar structure shown in Figs, and 11 hereina fter described. It is to be noted that stationarytorque arm 8 4;rnay be 10- cated ,in: a difierent radial position about :axis 55 by h tis bl 8 ai fi sn ole of is u hq t 89 radially disposed about opening 75"infbracket 66. lt is to be furthervnotedrthat collar 87 and the bored end torque a m. 4 ad al y m ag their esr ss iv end 'of elementfltl such asfltoifpreyentiradialspreadihgliof thet'split wall er the element end's in the regionsg where twistingtforces are applied to the'sprin'g element,.ai1d that the radial openings in ends 70a and 70b -ofjspring element .v slot 'in the cylindrical wall of the spring element, as indicatedfinFigs. 10 and 11 .;l

" According to Figs.,4 and [5} junction 63 of

pivotarms

61 and 62 is'a structurally sturdy portion of suspension v the frame; but the advantages .of a trailing relationship.

4 axis stem 7 90 and; axis155l Linkagef92 constitutes av p member designed'to include apivot pin projecting a "in; the samedirectionas pintle, 80 suchthat the central axis or; pivotpin is substantiallyparallel with the axis of the pintle;,Rotatablytreceivingpin is a shackle or linkage :92 tpivotally connected to an. endof axlet housing 5 8 by' means :of' a l shackle bolt t a? pillow block ,94 ri id1yno qn p of end such that the axis of bolt 93fis'inparallellrelationship.withirespeet to the iof Qs' PZ fl nwm 'I '6 connection between suspension member .60 and "end 5, I axle'housin'gj58 whichcornpensates for any lateral movemento'fpin 90 resulting from rotaryaction of the, sus pensionrnember about axis '55 and prevents undesirable movement of 'the axle housing relative to the; vehicle 1 V frame,fin a lateral direction; I m t Because of the above-described construction of spring suspension system B, movement of 'end 58a of axle housirig 58 relative to the vehicle frame is not only confined to a generally vertical plane extending transverselylof between wheel 54 and said frame are provided because of the obliquerelationship between hinging 'axis 5,5 of the suspension member 60 and the longitudinal axis 32' of the vehicle; thus, under conditions of forward motion,

wheel 54 is pulled overshock-producing roadways.

shank, 74 tightly held in an opening75' of bracket. 7

by a nut 76; while pivotal connection is effected by means of a rotative engagement between aborev79 in bracket 67 and a pintle 80 projecting'frorn one sideof the distal end of pivot arm 62, which pintle isprovided with a nut781 to minimize end play in'thevrotative engagement. v a

Springelementg issupported between

pivotal connections

64 and 65 such that theaxes of these connections and the longitudinal axis ofthe spring element are tcoincident with hinging axis 55. This supportedf'condition of element 70 is efiected by stub shaft 7210f connection 64, wliich is slidably received by'end70n' of the gspring element,"and by means axially aligned withjpintlef of connection 65 such as'a boss 82 formed on andprojectingfrom the other side of the distal end of pivot arm 62, which boss is slidably received bythe other end"70b" P FEf Torsionaldefiction-of springelement- 70 in-direct proportion topivotal movernent of suspension member 60 about axis 55 results from a 'nonrotating relationship, between spring element-70 and bracket 66 of the vehicle- 'frame,janda driving relationship between element 70'.

an 1M a m 62 of s s. m nbc fi -ji T I in t'andemrelationship under the Another spring suspension system identified by-reference letter C is illustrated in Figs. 7 through 13, which i is also characterized by-a tubular torsion spring similar in structure and function to spring element 20 of Fig. 1, and which, like system A and B is adaptable for use in wheeled vehicles, particularly those employing wheelsupporting axles ofvthe stationary or' driving varieties, or v a combination of these varieties disposed transversely load-supporting structures of the vehicles. t

For purposes of description, spring' suspension C is shown connecting respective ends a and 101a of tan demly arranged. wheel-supporting axles 100 and 101 to avehicle frame having a side member 102 and a longitudinal axis 103,tsuchthat the axles are disposed trans- 'versely j'of the vehicle frame at substantially; right angles with respect to the frame axis 103', and such that wheels 104 and i105. (schematically represented by circular lines" in Fig. 7 and fragmentary outlines in Fig." 8) resiliently support the load-carrying vehicle frame. As seen" in j Fig'si] and 8 a tubular spring element 106 having alo'ngi H tndinally slottedi'generally cylindrical wall and a central j axis 107 is supportingly coupled to frame side member of the wheel-supporting amass 102 by a br'aeket 108 -'(see Figs. 12 and 13 having portions 108a, 1081:, and -1-08ccircumaxi'ally embracing the wall of the spring element "so as 'to allow rotation of the latter, and portions 108d, {108e,and 108) secured to the frame side membersuc h that element axis 107 lies in a generally vertical plane extending lengthwise-of the vehicle frame at an oblique angle to frame axis 103; Disposed "on opposite sides of spring element 106 are suspension members 110 and 1 (Figs. 8 and '9) h'a'ving portions 111 and 111' provided "with divergent

piv'ot arms

112, 113 and 11 2', 113 having distal ends 114, 115 and 11 4, 115', respectively, 'of'whi'ch the distal ends'are constructed to circumaxially'embrace the spring element such as to permit relative movement 'therebetween.

Force transmitting connections between the'ends of spring element '106 and suspension jmembers "1'10 "and 110' are 'illustrated bythe "enlargedviews in Figs. '10 and 11, where a cap 'screw 116 is shown extending through radial-openings in distal end 114 ofarm "-112 'an'd the respective end of -spring element .106 into 'a threa'defd eng'agement with an alignment plug 118; The structures shown in Figs. 10 and 11 'are notyonly typical of the driving connections between the ends ,of element 106 and members 110 and 110', but they are also representative of the connections employed at the ends of tubular spring element 70 previously described "in connection with suspension system B shown in "Figs. 4 through 6. In other words, sectional views taken on planes passing through the longitudinal axes of capscrews 85'and 86 would be substantially-the same as Fig's. IOand 1 1, and

would show the axes of the cap screws diametrically aligned with the slot inthe wall of spring'elernent70..

Portions 111 and 111' of suspension members {110 and 1'10are designed to include pivot'pins "120fan'd 120 having central axes substantially parallelwith axis "107 of springelement 106. Rotatablyreceivingipins "120 and 120 are shackles or linkages 122'and 1'22piv'otally connected to wheel-supporting axles 100 and 101 by'means of shackle bolts 123, 123' and pillow blocks '124, 124 rigidly mounted ontop of axle'ends 100a and 101a, respectively, suchthat the axes of theshackle bolts "are parallel with-axis 107 and the axes of 'pivotpins 120 and 120'. The shackles or linkages '122'and 122'constitute 'means providing pivotal connections "between suspension members110, 110' and ends 1'00a'and 101a of the wheel-supportingaxles, which 'compen'satefor any lateral "movements of pins 120 "an'd'120' resulting from rotary actions of "these "suspension "members about axis 107, and prevent undesirable movement of "axles '100 and 101iin lateral directionwith respect to "thevehicle frame. Furthermore, 'the above described construction of spring suspension system C not 'only'operatesto 'confine relative movement between the wheel-supporting axles and'the frame of the vehicle to ge'nerally'verti'cal and substantially parallel planes extending transversely of said frame, but it also affords. a trailingrelationship between one of the axles and thevehicle"frameregardless of the direction of vehicle motion, because of the oblique disposition of axis '107 with'respe'ct to the "longitudinal frame axis'103. I J

Another unique feature of spring suspension system C resides in its ability to provide an equal'di'stribution of weight to'wheels 104 and "105 mounted on the ends of axles 100'and 101. This ability results from an equalizing relationship alforded bythe rotatably' supported condition of torsion spring element lfie inportions 108a, 108b,and 108c of bracket 1'0'8;'hencethe weight or the vehicle load-supporting structure is transmitted .to the axles and wheels by 'the spring element 'and the bracket as 'twistingforces applied to the ends of said spring elementin opposite directions about element axis'g107, which twistin forces-areof equal magnitude because of the 9 dimensional similarity -between suspension members 110 and'1'10.

Although the drawings show only a portion of one side of the load-carrying wheeled vehicles embodying suspensionsystems A, -B, and C, it is to be understood from the foregoing deser iptionso'f the several figures that the structures disclosed also :onstitute the spring suspension means connecting the right-front and right-rear wheel supporting structures to the vehicle frames in the cases of systems A and B, respectively, and the spring means connecting the other ends of the wheel-supporting tandem axles "to the vehicle frame in the case of system C. Moreover, it should be understood that system A is equally well adapted for use in connection with individually suspended'driving wheels or with combination driving and 'dirigible wheels; whereas systems B and C are equally well adapted to both driving and stationary wheel-supporting axles, or in the 'case of system C, to a combination of :a driving andPa stationary wheel supporting axle. 1 g

Another important "feature of jthe present "invention resides in the fajc't that reaction forces in suspension systerns -A, B, and Crresulting from braking and/or driving forces applied to the wheels of the vehicles are transmitted directly to the frames of the vehicles without producing torsional'deflections in'the respective tubular spring elements; This absence of torsional deflection provides a distinct advantage, since it'precludes-the'storage of energy in'the springs by the braking or driving forces applied to the wheels and the concomitant release or feeding back'of 'such'ener-gy to the "wheels "as "is "the case in conventional suspension systems. "In this connection, itis pointed out that feed-back "energy is a heavy contributor to "the destructive chatter occurring during clutching and/or braking "operations "of "transportation vehicles. I

"From the foregoing description, it'i's seen that suspension members '18, .60, and 110, cooperate with

spring elements

20,70 and 106, each having aj generally cylindrical waJl'with a longitudinally extending slot the full length of the wall, to providestructurallyfandfunctionally similar spring suspensionsystems A, B,rand'C, respectively, which are variously adaptable for use in a variety of vehicl'es'having different'ty'pes of wheel-supporting axles. Moreover, these systems are also characterized by other'similar advantages such as,.simple and sturdy design,'reduced manufacturing costs, elimination of spring'deflection causedby braking and drivingforces applied tothe wheels, elimination of brake and clutch chatter caused tbythefeed-backto the wheels of energy stored'in'thesprings, a trailing conditioniof the wheels to "minimize "road shock, a structural "condition wherein most of the suspension system weight is added to the sprung'weight of thevehicle, and adaptabilityto a wide range of vehicle "construction.

For the'sake of simplicity, 'a single tubular spring element'has been shown'in each of the three systems disclosed, however, it is to be understood thateach system may employtwo or-more tubular elements of the character described by arranging such elements in telescoped relationship abouta common axis and, depending upon the results desired, connecting the'telescoped elements in series or inparallel without departing from 'thespirit or scope of this invention. It'istobefurther understood that spring elements constructed as tubes having overlappingbut unconnected wall. portions maybeemployed when desired, and that such tubes are considered .within the scope of the meaning intended for split-.wallediubes.

What is claimed .as new. is:

1. "In a vehicle having wheel andload carryingtstmG- tures with spring suspension.meansinterconnectingsaid wheel :and .loadacarrying {structures such .that -.the loadcarrying .stmctureis .resiliently supported .byfthe wheel structure, .-.said. sprin .g suspension .means comprising: a

torsiona'llyffiexibletubularnspring elemeuthaving agenerally cylindrical wall; .said .wallbeing structurally contmuous except for a single wall-separating slot extending mamma s. o a asksement from, and in n;

a et-s r i s o n h t t hs fmrs ona n ina trs e ir mov m nt; with b p ta tween. the slot-forming wall portions accompanied by' concurrent tendencies of said slot-forming wall portions to move radially at theends of said spring element when opposing forces are twistingly applied tosaid element at aasaass.

flexibility of said spring element is characterized by longithe wheel structure as forces, twistingly applied to said spring element; said interconnecting means' comprising first and second devices nonrotatably connected in axially spaced 1 locations to the slotted generally cylindrical; wall ofthe {spring element foruapplying the a twisting. forces theretqsuch-g that the characterizinglongitudinal'jirelative moyement between, the slot-forming jwall portions is effected throughoutthe length of saidelement when said twisting forces are applied, said first and second devices being respectively mounted on the load-carrying structure and on one of the second and third portions of said suspension member such that up and down movement of the wheel structure relative to said load-carrying structure causes relative angular movement between the first and and a. longitudinal axis,

ins. a sener y tcrl dric l-sspar t ns s t m n in q s a y of aid sp i is characterized gby,longitudinal relative movement without rubbing gontact between the slot-forming wall portions accompaniedby concurrent tendencies of said slotformingwallportionsto move radially at the ends of said springelement ,when opposing forces are twistingly applied to said, element I at two locations on the general ly cylindrical wall; and said tubular spring element being supported from thej'load-carrying structure such that its 'longitudinal aagis isnfixed with respect to said. structure,

and such that, its characterizing torsional. flexibility is accomrnodated; .first means nonrotatably connectedto the tubular; spring element and mechanicallyassociated with the wheel ;and load-carrying structures such that ,weight f th ea -ca r in rus u' eis tr n i t d to th h structure as forces twistingly applied to said spring element at t 10c. .o ns lon c sl tsd sen l y m drical wall thereofsuchi that the characterizing torsional ficx i ymfa ai t nst sm szmain in s first I m ans-ins udinsa' pa rt fi i cer rai smi n arms having r t-en g bnsc u cdt th wheel t u t d ond end portions hingedly associated with the load-carrying structure such that said second end portions are disposed a distance apart and their hinging axes are subsecond devices about the hinging axis of said suspension I member; and means -circumferentially embracing the slotted generally cylindrical wall of the spring elementat the ends thereof such that radial movements 'of'the slotforming portions of said wall are precluded at said spring element ends when twisting forces are applied tosaid spring element by the first and second devices. a

2. The spring suspension means definedv in claim *1' wherein the first device of the interconnecting means is supportedly connected to the load-carrying structure in the region of the hinged connection between said structure and the other of said suspension member second I and third portions. I

3, The spring suspension means defined in claim l'in which one of the first and second devicesof the interconnecting means includes a portion so constructed and arranged as to constitute the means circumferen'tially embracing the slotted generally cylindrical wall at one end of the tubular spring element. 7

4. The spring suspension means defined in claim 1 in which the first and second devices ofthe interconnecting means include portions so constructed and arranged as to constitute the means circumferentially embracing the slotted generally cylindrical wall at the ends of the tubular spring element.

5. The spring suspension means defined in claim 1 wherein the first and second devices of the interconnecting means are nonrotatably connected to the generally cylindrical wall at the ends ofthe tubular spring element such that application of twisting forces to said element is effected in substantially diametric opposition to the slot in said wall.

6. The spring suspension means defined in claim l wherein one of. the first and second devices of the interconnecting means is nonrotatably connected to one end of the tubular spring element by a force-transmitting I element extending through a radial opening in the generally cylindrical wall in substantially diametric opposition to the slot in said wall...

7. In a vehicle having wheeland load-carrying struc- .tures interconnected'by spring suspension meanslsuch that the load-carrying structure is resiliently supported by the wheel structure, said spring suspension means comprising: a' torsionally flexible tubularspring element hav- -stantially aligned with the longitudinal axis of the spring element, the second end portion of one of said arms being nonrotatably connected to said spring element at one of the two locations on the generally cylindrical wall thereof,

' and the second end portion of the other of said arms being rotatable relative to said spring element and the loadcarrying frame about its own hinging axis; and second means circumferentially embracing the slotted cylindrical Wall of said spring element at the ends thereof such that radial movements of the slot-forming portions of said wall I are precluded at said' spring element ends and such that the longitudinal relative movement between said slotforming wall portions is unrestricted when twisting forces are applied to said spring element'by the first means.

8. The combination defined in claim 7 in which the first means is characterized by a supporting element mounted on the load-carrying structure and having a portion circumferentially embracing the slotted cylindrical .wall of the tubular spring element at one end thereof such as to constitute the second means to the extent that radial movements of the slot-forming portions of said .wall are precluded at said one spring end when twisting forces are applied to said spring; and in which said'first means is further characterized by a nonrotatable connection between said supporting element and said tion of said one arm for applying twisting forces to said I spring element, said nonrotatable connection being such that longitudinal relative movement of the slot-forming portions of the spring element walls is unrestricted by said connection when said twisting forces are applied.

9. The combination defined in claim 7 in which the first means'is characterized by the fact that the second end portionof said one of said" arms is .so constructed as to circumferentially embrace the slotted cylindrical wall of the tubular'spring element such as to constitute the second means to the extent that radial movements of the slot-forming portions of said wall are precluded at said one end of the spring element and such that longitudinal relative movement of the slot-forming wall portions is unrestricted by said second end portion when twisting forces are applied by said first means. i

10. The combination defined in claim 7 in which the first means ischaracterized by the fact that the second end portions of the pair of force-transmitting arms cir- ;,cumferentiallyembrace the slotted cylindrical wall of r the tubular spring element a distance apartfrom each I llbcins, tru turalhic ntinuo s exceptfor single I @Lmenti cmsud to and. s id sta para ing s o bein uc l ha theztq ional' xib tynt i p g le e other along said wall such that g'th'e axes of *said second end portions are coincident with the longitudinal axis of said tubular spring element and "such that one of *said second end t-portio'ns is disposed at-one end of said spring element thereby constituting the second means to the extent that radial movements of the slet-forming 'portions of said cylindrical 'wall are precluded; and :by the fact that said onesecond end portion is nonrotatablyconnected to said one end-of the tubular spring element for applying twisting forces thereto such that longitudinal relative movement 'of the slet-forming wall portions of the spring element wall is unrestricted.

11. The combination defined *in claim '7 in which the first means is characterized by first and second pairs of force-transmitting arms, each "pair of arms having first end portions *coupled *to the *vhile wheel "structure and second end portions liingedly associated with the loadcarrying structure "such that the =second end portions of each pair of arms 'eircumferen'tially embrace the slotted cylindrical wall of the tubular spring "element and are disposed adistanee "apart from each other 'along said slotted 'wall with their axes "coincident *with the longitu'dinal'axis of said springelement, one-second' end'portion of one arm of each pairof arms being =nonrotatably connected to one end of "the tubular spring element for messes 1'2 applying twist'in'g forces to said spring element at the two locations along-the "slotted cylindrical *wall -suc'h that radial *movements of the slot-forming portions of said wall are precluded "and longitudinal relative movement between said slot-forming portions is unrestricted when twisting forces-are applied by the two -pairsofarm's.

12. The combination defined in claim 7 in which the first means includes nonrotatable connections with the generally cylindrical wall of the springelement at two =10- cations substantially diametrically opposite the wall-separating slot, at least one of said two locations being adjacentone end of said spring element.

"References Cited in the L-file of-this patent UNITED STATES PATENTS Germany 3 Nov. 1 7, 1944